Sensitive quantification of 5F-NNEI and characterization of its several metabolites in authentic urine and/or serum specimens obtained from three individuals by LC–QTRAP-MS/MS and high-resolution LC–Orbitrap-MS/MS
A synthetic cannabinoid 5F-NNEI and its metabolites in authentic human specimens have not been reported yet. The aim of this study is, firstly, to establish a sensitive quantification method of 5F-NNEI in human serum and urine specimens, and, secondly, the characterization of its metabolites in authentic urine specimens obtained from three individuals.
These compounds were extracted from β-glucuronide-hydrolyzed and unhydrolyzed urine and/or serum specimens via liquid-liquid extraction. The identification and quantification were performed using liquid chromatography (LC)–QTRAP tandem mass spectrometry (MS/MS), and the characterization of the metabolites was done using LC–high-resolution-MS/MS.
The limits of detection for unchanged 5F-NNEI were 6 pg/mL with the quantification range of 10–2000 pg/mL in serum, and 3 pg/mL with the quantification range of 5–1000 pg/mL in urine. The devised method was applied to quantify 5F-NNEI in authentic serum and/or urine specimens from three individuals. The levels of 5F-NNEI were 11.6 and 3680 pg/mL in serum specimens of cases 1 and 2, respectively, and were 5.07 and 7.90 pg/mL in urine specimens of cases 2 and 3, respectively. Several metabolites of 5F-NNEI produced by amide hydrolysis, defluorination, hydroxylation, carboxylation and/or glucuronization were tentatively identified in the urine specimens by the LC–high-resolution-MS/MS.
A synthetic cannabinoid, 5F-NNEI, was identified and quantified in its unchanged form, and its several metabolites were tentatively identified in authentic specimens obtained from three individuals, for the first time to our knowledge.
Keywords5F-NNEI In vivo metabolites in urine QTRAP mass spectrometry High-resolution mass spectrometry Authentic serum and urine specimens
This work was supported by JSPS KAKENHI Grant Number JP16K09206.
Compliance with ethical standards
Conflict of interest
The authors declare that there are no financial or other relations that could lead to a conflict of interest.
All procedures performed in this study involving human participants were in accordance with the ethical standards of the international and/or national committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. The analysis of the substances from the individual who was suspected by the police of having used illegal drug(s) was permitted by judicial authorities and supported by official documentation. In addition, 5F-NNEI had not been controlled/regulated in July and August 2013 in Japan, when all the authentic human specimens were brought to our laboratory. Informed consent was obtained from all participants included in the study, who supplied about 10 mL each of blood and/or 40 mL each of urine for use as blank specimens.
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